USA001 - Gabion Mats -Erosion Control -NM - Maccaferri

EROSION CONTROL CHANNEL LINING
Product: Gabion Mats
Problem
The owner of a mining claim in central New Mexico elected to
close the property because of declining commodity prices.
In order to close the mining operation it was necessary to install
a spillway ‘overflow’ over the existing dam to control the volume
of impounded water.
The existing dam was of a clay core construction. The spillway
had to be designed to limit the significant shear forces and
erosion in the overflow channel. Also any erosion control solution
had to accommodate local differential settlements. The expected
shear forces would exceed that offered by a high performance
permanent erosion control mat, and a more robust solution was
required. The strength and flexibility of double twisted mesh
gabion mats offered an ideal solution.
Solution
With the assistance of Maccaferri’s Technical Department, the
project engineer detailed a series of eight connecting gabion
drop structures. These controlled the water level over a 24 foot
change in elevation from the dam crest to the flow level in the
existing drainage channel. By converting kinetic to potential
energy, the erosion shear forces were reduced.
The drop structures were designed in part using Maccaferri
design software; “Macra 2” for the drop structures, and “Macra
1” for the channel. “Macra 1” is available to designers and
contractors if required
Following discussions with the project team, Maccaferri
manufactured 99’ long Gabion Mats with 3’x3’ cells to reduce
the cost and time of the installation through economies of scale.
In addition, 27’ and 51’ long Gabion Mats were also specially
manufactured to suit the site requirements, further helping the
contractor.
Designer:
Client name:
MACCAFERRI INC.
Product used:
GABION MATS, RENO MATTRESSES, MACTEX MX275
Date of building:
SUMMER 2001
CASE HISTORY
Ref: USA001 - Rev: 001, Issue Date 12.12.2003
EROSION CONTROL OF MINE SPILLWAY
MARQUEZ, NEW MEXICO, USA
Channel & terrace preparation
Drop structure detail
Macra 1 design software by Maccaferri

4.5'
Typical long section through a drop structure
Retention pond at low water
Drop structure at low water
Headquarters - East Coast
10303 Governor Lane Blvd, Williamsport, MD, 21795
Tel.: (301) 223 6910 Fax: (301) 223 4356
6' 30' 3' 12'
3'
1.5 ft. thick Gabion 1.5 ft. thick Gabion
1.0 ft. thick Gabion Filter Fabric
Mactex MX 275
MACCAFERRI INC.
E-mail: hdqtrs@maccaferri-usa.com
Web site: www.maccaferri.com
1.5'
The Gabion Mats were constructed upon a non-woven
needlepunched geotextile - Maccaferri MacTex MX275. This acts
as a separation and filtration layer between the foundation
material and the gabion erosion protection. The geotextile limits
the “wash-out” of fine material from beneath the Gabion Mat
under high flows and storm conditions.
If local erosion does occur beneath the mats, the flexibility of
the double twist mesh allows the gabion to settle and continue
protection without sustaining damage.
The Maccaferri double twist hexagonal mesh was PVC coated
due to the water environment. Double twist mesh is very robust,
and can accommodate large differential settlement without
rupturing or ‘unzipping’. The junction strength, or weave, between
adjacent wires in the mesh is as strong as the wire itself.
Stresses in the mesh can therefore be dissipated in two
dimensions throughout the mesh. This ability continues even if
wires are cut or damaged.
This is a vital characteristic particularly in critical infrastructure
applications where there is the potential for differential
settlement.
Working with Maccaferri
For over 120 years, Maccaferri has provided engineering
expertise to clients around the world. We believe that
the combination of our professionalism, design software,
technical and site assistance service and our aim of
providing the best products in the market, sets us apart
from our competition. We hope you agree.
West Coast
3650 Seaport Blvd, West Sacramento, CA 95691
Tel.: (916) 371 5805 Fax: (916) 371 0764
Copyright 2004 Maccaferri Inc.